Hey everyone. Got an 06 F350. I have a LN 230 alternator with the upgraded wiring kit. Recently I was driving and the truck started running rough and the electronics in it shut down. I was able to get my wife to come out and give me a charge, got the volts to 11ish and was able to get it home. The voltage dropped to 7ish.

Brought the batteries in and one was bad. It wouldn't accept a charge. Bought two new batteries. The old ones were 4.5 yrs old. I put them back in, but then noticed the high output lead on the back of the alternator was melted through at the eyelet. Drove the truck today for about an hour. Lost approx .4 volts. I still have the other aftermarket lead from the alternator to the passenger battery, so I figured it would charge.

What am I looking here? Could the bad battery cause a short and cause that wire to melt off. Gonna pull the alternator and get it tested. Hope that didn't fry. Also does anyone if the main lead leads anywhere other than the battery or is it tied in to other places? Thanks in advance.

 

That would happen from a loose crimp or the wires starting to break, developing into a smaller wire as the strands break. With the L-N being a taller alternator, it does put more stress on the wires. The later model trucks are more so, as I believe your factory alternator was clocked counterclockwise, so there was less strain on the wires.

Something is still off, though. That added cable should have provided a good enough path for you to not lose any charging, to the point of not noticing anything.

The factory cable could be opened up and cut back so a splice can be added as a replacement with a longer length.

You should take some images of the positive passenger terminal so we can see what that looks like, too, to understand this situation better.

 

TooManyToys, thanks for the reply. Just want to start off by saying I've been reading your posts and watching your videos for years. So thanks for that as well.

I'll attach some pics down below. I noticed some corrosion on the passenger terminal. That extra wire you see is to an small horn.That wire and fuze for that horn all appear to be in intact and not cut or anything.

Was gonna get the alternator checked. I think I'm just concerned that if I buy a new alternator and reattach that main lead I might kill that alternator. Since I replaced the batteries in my mind the "short" or resistance or whatever wouldn't be there anymore. But I guess I really don't understand electricity....lol.

​​​​​​This may be the dumbest question you've ever gotten, but If I install a new alternator start up the truck and go to attach the lead, would there be a dead give away something was wrong. (Ie shower of sparks) Then I would know not to attach it.

Do you happen to know when that lead leaves the alternator where it goes? It appears to go down to wiring harness but then is wrapped up so I can't follow it. If not I can start cutting into it to trace it out and make sure the line is still good. Unless you don't think that would be necessary.

 

Thank you.

You don't necessarily need a new alternator; never connect or disconnect an alternator while it's running—a good way to blow it.

The first thing I would do is check the fuse in your additional cable layover. That may have blown, and why your OE cable is burned.

The factory cable feed is shown in this diagram. Two grey fusible links in series protect the alternator to the battery path. At the fusible link juncture, other fusible links are connected. Two of the same size go to each bank of the glow plug controller, and a smaller one goes to the alternator to sense the battery and system voltage. Those could get fed through the additional layover cable if the alternator fusible links or cable (as is yours) are separated.





These images show the path of the OE factory alt/batt cable. It gets wrapped into the main engine harness, but if you had to, the tape covering could be removed, and the alternator cable and sense wire removed. Fusible links are never covered with tape.













As I mentioned, I am suspicious of your add-on fuse. However, with the fuse in working condition, you should not have noticed anything that your factory cable had separated.

The coloration of the factory wire strands indicated it had overheated, possibly for some time due to the dark and green color. You also might want to remove the grease on the battery terminal and check it for corrosion. There appears to be a little green, but it would not have caused this.

Also, you might want to get a replacement two-wire connector for the alternator at some point. The connectors (cheap) come with leads, so you could do as I have, make the wires longer, so there is not as much strain on the cable as the wires hold up the entire harness with this situation of a taller alternator.

 

Awesome, thank you very much for the write up. I'll pull the alternator tomorrow to get checked. Additionally I'll trace out the main lead and throw a new eyelet on the end. Would it be safe to assume if the fusible links are still good that the cable itself would be as well?

 

Yes, it should be. You might have an issue with the cable length, putting on an eyelet.

You can check the fusible links easily with the wiring just as it is. Check the voltage at the end of the burned cable, but be careful not to short the cable against any metal. Or with both ends of the cable disconnected, use an meter to check ohms or continuity. Also when fusible links blow, the insulation gets colored. These being grey, easy to tell. But measuring is the best course.

 

Got everything hooked back up and it's ready to go. I pulled the alternator and had it tested. It was still good. While I had it out, I checked the fusible end links and those looked good as well. After reinstalling the alternator and crimping on a new eyelet I was able to reconnect everything with no issues. I started up the truck and everything has been running well. I'm sitting at right around 14v.

I think it's safe to assume that your theory was correct about the crimp not holding up, or just slowly burning off. I'll have to look into extending out that eyelet some more though. It's still weird to me the other cable didn't seem to charge the batteries. I'll look into that a bit more as well.

Thanks for all your help. Like I've said, I've watched many of your videos. You and DieselTechRon (RIP) actually helped me make the decision to buy the truck, rebuild it and tackle every possible issue that could happen right away. This truck has been unbelievably reliable for the past 5 years. So again, thank you!!

 

Glad to help.

When the truck of course is not running, you could check ohms or continuity of the cable end to end. And fuse.

Another with the cable connected at the battery but disconnected at the alternator, check for battery voltage. You just don't want to touch the disconnected eyelet to a grounding source.